Antihistamine Effects on the Central Nervous System, Cognitive Performance and Subjective States

Abstract

Diphenhydramine causes drowsiness and performance decrements in some tasks whereas terfenadine generally does not. This study examined central nervous system (CNS) differences in response to the administration of diphenhydramine (50 mg) and terfenadine (60 mg) up to 3 h after drug administration. Two evoked potential measures, the Brainstem Auditory Evoked Potential and the Pattern Reversal Evoked Potential (PREP), assessed CNS function. Other measures of CNS function, cognitive performance and subjective states administered included Critical Flicker Fusion, the Baddeley Grammatical Reasoning Test, Digit Symbol Substitution, the Profile of Mood States, and the Environmental Symptoms Questionnaire. Significant increases in PREP latencies (N75, P100 and N145) occurred after orally ingesting diphenhydramine. No other significant drug effects were observed. The significant increase in the PREP latencies indicate diphenhydramine’s presence in the cerebral cortex results in a slowing of visual information processing. The lack of significant findings for terfenadine is probably a result of its difficulty in penetrating the blood-brain barrier.

Tracking the Cognitive Pharmacodynamics of Psychoactive Substances with Combinations of Behavioral and Neurophysiological Measures

“…In the current study we found that responses were significantly slower and less accurate following ingestion of diphenhydramine relative to the other test conditions. Similar effects have been observed in prior studies that have examined performance following diphenhydramine administration in subject populations and under dosing ranges and procedural conditions approximating those in the current study (Fine et al 1994b;Oken et al 1995;Rice and Snyder 1993;Tharion et al 1994). Of particular interest is the observation that the behavioral impairment produced by 50 mg of diphenhydramine was substantially greater than the behavioral change observed following a dose of alcohol adequate to raise blood alcohol to the Figure 7.…”

Antihistamines: models to assess sedative properties, assessment of sedation, safety and other side‐effects

“…Tests of car driving feature in 15 studies and appear to be sensitive to the sedative effects of antihistamines. It has been suggested that the ability of the driver to control weaving of the car, measured as the standard deviation of the lateral position, is an indicator of drug‐induced sedation [7]. Such tests represent low level global motor performance and do not assess more important functions, e.g.…”

Workshift and antihistamine effects on task performance

“…Several studies have shown that these newer, non-sedating antihistamines have few, if any, negative effects in comparison to the earlier H 1 -blocker antihistamines. For example, it has been shown that newer, non-sedating antihistamines have no apparent negative effects on various cognitive and psychomotor abilities (Cingi, Cingi, & Cingi, 1990;Clarke & Nicholson, 1978;Fink & Irwin, 1979;Kulshrestha, Gupta, Turner, & Wadsworth, 1978;Nesthus, Schiflett, Eddy, & Whitmore, 1991;Nicholson & Stone, 1982;Nicholson & Stone, 1986;Philpot, Biegalski, & Brooker, 1993;Reeves, Blackwell, Molina, & Hixson, 1989;Rice & Snyder, 1993;Snyder & Berg, 1990;Tharion, McMenemy, & Rauch, 1994;Witek, Canestrari, Miller, Yang, & Riker, 1995). They also do not appear to disrupt EEG activity (Loring & Meador, 1989;Stephens, Caldwell, Comperatore, Pearson, & Delrie, 1992;Tharion et al, 1994) or more basic sensory-psychophysical functions (Fink & Irwin, 1979;Kulshrestha et al, 1978;Nicholson, Smith, & Spencer, 1982;Nicholson & Stone, 1982;Nicholson & Stone, 1986), and they do not typically influence self-reported levels of subjec-• tive state (Philpot et al, 1993;Reeves et al, 1989;Tharion et al, 1994).…”